Certain television receivers are able to display multiple different pictures on its screen simultaneously. For example, a main picture is displayed on a full screen while at least one (and possibly several) sub-picture selected from another channel or a video system is displayed at a corner of the screen replacing the corner portion of the main picture. The main picture and the sub-picture(s) respectively accompany audio signals and caption signals.
FIG. 5 is a block diagram showing part of a conventional television receiver with a caption display. A video signal V1 from a tuner and multiple video signals V2, V3 and V4 are supplied to a video signal select switch 1. The video signal select switch 1 is controlled by a video control signal CLV from a control circuit 100. A first one of those video signals is selected as a main video signal MAIN by the control signal CLV in the video signal select switch 1. The selected video signal is supplied to a closed caption decoder 2 (referred to as "CCD" hereinafter) and an integrated circuit 3 (referred to as "YCJ" hereinafter) which modulates a video signal and deflects the modulated video signal. A second one of those signals is also selected as a sub-video signal SUB by the video control signal CLV in the video signal select switch 1. The selected video signal SUB is supplied to a picture-in-picture circuit 4 (referred to as "P-IN-P" hereinafter).
The main video signal, the caption signal separated from the main video signal by CCD 2 and the sub-video signal shaped by the P-IN-P 4 are superposed in YCJ 3. The superposed signal is supplied to a CRT (not shown). Therefore the main picture, the caption corresponding to the main picture and the sub-picture are displayed at a certain position on the screen.
An audio signal A1 corresponding to the video signal V1, audio signals A2, A3 and A4 respectively corresponding to the video signals V2, V3 and V4 are supplied to an audio select switch 5. The audio signal select switch 5 is controlled by an audio control signal CLA from a control circuit 200. One of those audio signals is selectively output to a speaker or earphone (not shown).
However the caption signal CA accompanying the main video signal MAIN is only displayed on the screen in the conventional television receiver with a caption display. The caption signal accompanied by the sub-video signal or another video signal is not displayed on the screen. In such a system, the user cannot freely select a picture and a caption as the user pleases.